In the mounting of electrical fixtures, receptacles, switches and the like in the interior of buildings, it is common practice to mount electrical junction boxes to ceiling joists, wall studs or other members of the building's structure. When mounting such devices on the exterior of a building or structure, particularly one that is covered or to be covered with siding of one type or another, it is significantly more difficult to obtain a secure mounting location that also provides an esthetically pleasing or at least acceptable appearance.
A large number of devices have been suggested to obtain an acceptable electrical junction box for installation on the exterior of a building. Such electrical junction boxes are commonly referred to as "flush-mount" boxes because they give the appearance of being attached to the surface of the building and do not require attachment to a stud or other building frame member and yet they are secure and esthetically acceptable.
U.S. Pat. No. 5,549,266 to Mitchell et al describes a two-part exterior mounting bracket that includes a back plate that incorporates a deflecting strip to inhibit the penetration of water behind the siding of the structure. Successful use of this device requires its careful location with respect to the over-applied siding to insure that the deflecting strip does not interfere with the proper installation of the siding.
U.S. Pat. No. 5,326,060 to Chubb et al describes a one-piece plastic building wall mount assembly for the installation of electrical receptacles and the like on the exterior surface of a building. The device comprises a one-piece bracket with a back wall and an integral continues peripheral wall extending axially therefrom, a flange member having an outside flange and an integral flange wall extending axially therefrom to be received by the mounting bracket so that only the flange member is visible from the outside of the building. This device offers significant risk of water permeation about the periphery of the integral flange wall after installation and is therefor not entirely satisfactory.
U.S. Pat. No. 5,722,208 to Humphrey et al describes a wall mount system for electrical devices comprising a one or two-piece wall mounting frame with an integrally molded electrical junction box which is flush mounted on the exterior of a building. The devices described in this patent include a narrowed gap between an interior flange and an exterior flange to allow proper fit with siding while maintaining the required depth of the electrical junction box. Although this approach is superior to many other such devices, the presence of the interior flange as a permanent part of the device requires cutting a very large hole in the siding to accommodate the interior flange when a retrofit installation is attempted.